Alternating current (a.c.) universal motors are commonly used in electrical power tools, such as, for example, circular saws, reciprocating saws and drills, and other types of equipment. Generally, these motors are a high-power, light-weight drive source for electric tools.
Typically, a universal motor includes a field or stator assembly and a rotatable arbor or shaft having an armature mounted thereon. Current flowing through a run coil of the stator assembly creates a magnetic field that interacts with the armature to rotatably drive the arbor in a direction of rotation. A tool element, such as a saw blade or drill bit, is coupled to the arbor and driven by the motor.
A typical field assembly includes an insulated field core having a winding support and a wire or winding wound on the core and the winding support. The field assembly may also include a terminal assembly to which the ends or leads of the winding are terminated for easy connection with other components of the motor.